Conventional cellular wireless communication systems can typically be characterized as: voice-centric; operative in an exclusive frequency spectrum; capable of providing relatively long-range wireless communication links (e.g., 5 km); capable of providing relatively low latency; and utilizing frequency management techniques to provide a relatively high quality of service (QoS). Conventional wireless local area networks (WLAN) can be characterized as: data centric; operative in a non-exclusive frequency spectrum; having relatively high latency; having relatively short-range wireless communication links (e.g., 100 m); and having a relatively low QoS due to the inherent interruptions associated with use of interference mitigation techniques.
As communications applications become more and more sophisticated, there is an ever increasing demand for wireless communications at higher data rates. Although WLAN can typically provide higher data rates (e.g., 11 Mbps) than cellular systems (e.g., 10 Kbps), nevertheless cellular systems can outperform WLAN systems in terms of range, latency and QoS.
FIG. 1 graphically illustrates examples of spectrum utilization in exclusive-spectrum systems such as conventional cellular telephone systems. As shown in FIG. 1, various users, designated as 1-8 in FIG. 1, are assigned time slots for communication at a given frequency A. These time slots are generally adequate for conducting voice calls, and even for conducting some data communication sessions that do not require an appreciably higher data rate than a voice call. However, in order to support a data communication session at, e.g., four times (4×) the data rate of a typical voice call, four of the time slots of FIG. 1 would need to be assigned for the desired communication session. Thus, the user would utilize 4× the capacity of a typical voice user. Considering a hypothetical user who, at the 4×data rate, uses the same amount of calling time as another user who makes only voice calls, the 4× user will utilize 4× as much capacity as the voice call user, which would generally result in the 4× user bearing a cost that is 4× as large as the voice call user's cost. For example, if the voice call user's subscriber cost is $50.00 per month, then the 4× user's subscriber cost could be $200 per month.
Moreover, the 4× user's monopolization of capacity is disadvantageous to the cellular operator even if the 4× user is willing to pay the $200 per month for his desired service, because the cellular operator will no longer be able to support the same number of voice call users with the same QoS as would be the case if there were no 4× user.
Thus, although the range, latency and QoS characteristics of exclusive-spectrum systems such as cellular systems are superior to non-exclusive-spectrum systems such as WLAN, nevertheless exclusive-spectrum systems are not generally designed to support the type of high data rate calls supported by non-exclusive-spectrum systems.
It is desirable in view of the foregoing to provide an approach to wireless communication that can achieve conventionally unavailable combinations of characteristics such as data rate, latency, QoS and range.